COREB: TESTING/IMAGING Core B, "Testing/Imaging" will oversee the construction and servicing of the various test instruments, field test newly developed ETF/imaging protocols and perform all testing required by Projects 1 through 4. The specific aims of Core B are to: 1) construct and instrument a pressure-chamber for testing ETF in ears with intact tympanic membranes;2) evaluate the comparability of ETF test results obtained using the pressure-chamber and those obtained using our standard test methodologies;3) perform all ETF tests and imaging studies required by Projects 1-4;4) maintain all testing instruments in good working condition;5) maintain calibration records on all instruments and quality assurance documentation for data reports to the Project investigators;6) assist the investigators in interpreting test results and in designing supplemental testing/imaging protocols, and 7) interact with the Pis of Project 1 and Core C with respect to feedback between test results and model simulations. Over the 5-year study period, the anticipated effort distribution of Core B is approximately 10% Core C, 20% Project 1, 20% Project 2, 20% Project 3 and 30% Project 4.